Apollos was a devout Jew from Alexandria in Egypt.  The Lord had opened his heart to believe in Jesus: how that happened or who was involved in leading him to Christ, we do not know.  But we do know that he was eager to travel all the way across the Mediterranean Sea to Ephesus to share this good news.  With the help of Priscilla and Aquila, who Paul had taught in Corinth, Apollos understood more of the gospel and gained the respect of the little church which was developing in Ephesus (Acts 18:24-26).

The Lord then stirred his heart to move on elsewhere.  Having heard about the church Paul founded in Corinth, from Priscilla and Aquila, he wanted to teach the new believers in that city and win more new converts.  The church in Ephesus agreed.  They understood that God moves His people around the world, and so it was not right to hold onto Apollos, but to release him in love and prayer.  They also wrote a letter to the church in Corinth, validating Apollos as a true minister of the gospel, unlike so many who wanted to invade the church with false teaching (2 Corinthians 11:13-15).

The route to Corinth was by sea.  No other city is mentioned in Achaia (now the most southern part of Greece with Corinth as its capital); so we assume he took the trading route across the Aegean Sea from Ephesus to Cenchrea (the port just south east of Corinth).  When Apollos arrived, he had three roles, as teacher to the new believers, and as evangelist and apologist to the Jews.  He was able to argue the case for the messiahship of Jesus.  His public gospel declarations greatly encouraged the little church, watering the Word which Paul had planted (1 Corinthians 3:6).

Like Apollos, we have no way of knowing what the Lord will lead us into as He urges us to move with Him.  The Ephesian church could not know what challenges Apollos might face.  All they knew was that if the Lord calls, He equips; where He sends, He provides; whatever the danger, He protects.  That is why it is safe to move as the Lord calls us.  When we start our work for the Lord, we have no idea where the ministry will take us.  But if our hearts are full of devotion to Jesus, His gospel will matter to us, and we will be willing to serve in whatever way will enable people to repent and welcome Jesus (1 Corinthians 9:22).  We may be called to plough or plant, water or weed, or harvest.  God only knows how He wants us to serve Him so that He will populate heaven by His grace.  But He will give us a desire to get started; after that - follow where He leads and leave the rest to Him.  The only thing that matters is being obedient to His calling (Acts 26:19).